From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934393AbeB1P7a (ORCPT ); Wed, 28 Feb 2018 10:59:30 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44524 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934015AbeB1P70 (ORCPT ); Wed, 28 Feb 2018 10:59:26 -0500 Subject: Re: [PATCH v2 04/15] KVM: s390: CPU model support for AP virtualization To: David Hildenbrand , Christian Borntraeger , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, cohuck@redhat.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com References: <1519741693-17440-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1519741693-17440-5-git-send-email-akrowiak@linux.vnet.ibm.com> <38deecae-53b4-c5cb-3dba-24bdfab3d9d0@redhat.com> <3a3ff176-4e6b-963c-7831-cdcd10b556eb@de.ibm.com> <10cfdb2a-304c-989b-4765-84e19fcd423f@redhat.com> From: Tony Krowiak Date: Wed, 28 Feb 2018 10:59:17 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <10cfdb2a-304c-989b-4765-84e19fcd423f@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18022815-0056-0000-0000-000004260D35 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008602; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000254; SDB=6.00996371; UDB=6.00506534; IPR=6.00775695; MB=3.00019779; MTD=3.00000008; XFM=3.00000015; UTC=2018-02-28 15:59:22 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18022815-0057-0000-0000-000008680D30 Message-Id: <06f77e0c-a99f-b8c8-750e-7ba148d374ed@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-28_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802280193 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/28/2018 06:58 AM, David Hildenbrand wrote: > On 28.02.2018 12:40, Christian Borntraeger wrote: >> >> On 02/28/2018 10:48 AM, David Hildenbrand wrote: >>> On 27.02.2018 15:28, Tony Krowiak wrote: >>>> Introduces a new CPU model feature and two CPU model >>>> facilities to support AP virtualization for KVM guests. >>>> >>>> CPU model feature: >>>> >>>> The KVM_S390_VM_CPU_FEAT_AP feature indicates that the >>>> AP facilities are installed on the KVM guest. This >>>> feature will be enabled by the kernel only if the AP >>>> facilities are installed on the linux host. This feature >>>> must be specifically turned on for the KVM guest from >>>> userspace to allow guest access to AP devices installed >>>> on the linux host. >>>> >>>> CPU model facilities: >>>> >>>> 1. AP Query Configuration Information (QCI) facility is installed. >>>> >>>> This is indicated by setting facilities bit 12 for >>>> the guest. The kernel will not enable this facility >>>> for the guest if it is not set on the host. This facility >>>> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP >>>> feature is not installed. >>>> >>>> 2. AP Facilities Test facility (APFT) is installed. >>>> >>>> This is indicated by setting facilities bit 15 for >>>> the guest. The kernel will not enable this facility for >>>> the guest if it is not set on the host. This facility >>>> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP >>>> feature is not installed. >>>> >>>> Reviewed-by: Christian Borntraeger >>>> Reviewed-by: Halil Pasic >>>> Signed-off-by: Tony Krowiak >>>> --- >>>> arch/s390/include/uapi/asm/kvm.h | 1 + >>>> arch/s390/kvm/kvm-s390.c | 4 ++++ >>>> arch/s390/tools/gen_facilities.c | 2 ++ >>>> 3 files changed, 7 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h >>>> index 4cdaa55..a580dec 100644 >>>> --- a/arch/s390/include/uapi/asm/kvm.h >>>> +++ b/arch/s390/include/uapi/asm/kvm.h >>>> @@ -130,6 +130,7 @@ struct kvm_s390_vm_cpu_machine { >>>> #define KVM_S390_VM_CPU_FEAT_PFMFI 11 >>>> #define KVM_S390_VM_CPU_FEAT_SIGPIF 12 >>>> #define KVM_S390_VM_CPU_FEAT_KSS 13 >>>> +#define KVM_S390_VM_CPU_FEAT_AP 14 >>>> struct kvm_s390_vm_cpu_feat { >>>> __u64 feat[16]; >>>> }; >>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >>>> index de1e299..c68ca86 100644 >>>> --- a/arch/s390/kvm/kvm-s390.c >>>> +++ b/arch/s390/kvm/kvm-s390.c >>>> @@ -347,6 +347,10 @@ static void kvm_s390_cpu_feat_init(void) >>>> >>>> if (MACHINE_HAS_ESOP) >>>> allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); >>>> + >>>> + if (ap_instructions_installed()) /* AP instructions installed on host */ >>>> + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); >>> Don't we have a SIE specific AP feature? So is it true, that once we >>> have AP instructions, we are allowed to use them for SIE? Isn't there a >>> "AP interpretation facility" or anything like that? (that unlocks ECA_APIE) >> This seems to be coupled to the AP facility and there is no facility or scp bit. >> AP is too old to have that (predates STFLE) >> > Interesting, so we (I :) ) didn't implement vSIE support back then > because we never indicated the AP facility (sensed by executing the > instruction) to the guest. > > So ECA_APIE can be used when we sense the AP facility. Thanks! All true. >